Download or read book Soot Emissions from Turbulent Diffusion Flames Burning Simple Alkane Fuels written by Pervez M. Canteenwalla and published by . This book was released on 2007 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soot in Combustion Systems and Its Toxic Properties written by J. Lahaye and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions.
Download or read book Soot Production and Thermal Radiation from Turbulent Jet Diffusion Flames written by and published by . This book was released on 1910 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this study is to advance the present capability for modelling soot production and thermal radiation from turbulent jet diffusion flames. Turbulent methane / air jet diffusion flames at atmospheric and elevated pressure are studied experimentally to provide data for subsequent model development and validation. Methane is only lightly sooting at atmospheric pressure whereas at elevated pressure the soot yield increases greatly. This allows the creation of an optically thick, highly radiating flame within a laboratory scale rig. Essential flame properties needed for model validation are measured at 1 and 3 atm. These are mean mixture fraction, mean temperature, mean soot volume fraction, and mean and instantaneous spectrally resolved radiation intensity. These two flames are modelled using the parabolic CFD code GENMIX. The combustion / turbulence interaction is modelled using the conserved scalar / laminar flamelet approach. The chemistry of methane combustion is modelled using a detailed chemistry laminar flame code. The combustion model accommodates the non-adiabatic nature of the flames through the use of multiple flamelets for each scalar. The flamelets are differentiated by the amount of radiative heat loss that is included. Flamelet selection is carried out through the solution of a balance equation for enthalpy, which includes a source term for the radiative heat loss. A new soot model has been developed and calibrated by application to a laminar flame calculation. Within the turbulent flame calculations the soot production is fully coupled to the radiative loss. This is achieved through the use of multiple flamelets for the soot source terms and the inclusion of the radiative loss from the soot (as well as the gases) in the enthalpy source. Spectral radiative emission from the flames has been modelled using the RADCAL code. Mean flame properties from the GENMIX calculations are used as an input to RADCAL.
Download or read book Hydrodynamic Effects on Soot Formation in Laminar Hydrocarbon fueled Diffusion Flames written by Guozheng Lin and published by . This book was released on 1996 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soot Production in a Turbulent Diffusion Flame written by Jerry Alan Hoover and published by . This book was released on 1978 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Pressure and Fuel Structure on the Soot Yield of a Turbulent Diffusion Flame in a Crossflow written by Bruce Tobis and published by . This book was released on 1983 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Emissions from Free Turbulent Diffusion Flames written by Farag M. Imhamed and published by . This book was released on 1996 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fuel Structure and Pressure Effects on the Formation of Soot Particles in Diffusion Flames written by Robert J. Santoro and published by . This book was released on 1988 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the first year of the present grant, efforts have concentrated on examining the effects of fuel molecular structure on soot formation in diffusion flames. Studies involving alkane, alkene, alkyne and aromatic fuel species have been studied with specific attention given to the surface growth process. Analysis of these studies has demonstrated a strong fuel structure dependence for the amount of soot formed, the conversion percentage of fuel carbon to soot, and the soot particle surface area present in these diffusion flames. However, when surface area taken into account, similar specific surface growth rate coefficients are observed for all the fuels studied. These results point to a similar surface growth process for all the fuels. Consistent with premixed flame results, the present studies show a continual decrease in this specific surface growth rate coefficient with time. Other effects of fuel structure observed include an acceleration of the inception of soot particles to lower locations and, thus, earlier times in the flame as soot conversion percentage increases. These results also point to the importance of the initial particle inception process which appears to control subsequent soot particle evolution. Keywords: Soot formation; Soot particles; Diffusion flames.
Download or read book Combustion Generated Fine Carbonaceous Particles written by Andrea D'Anna and published by KIT Scientific Publishing. This book was released on 2014-08-13 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices.
Download or read book Flame and Combustion written by J.F. Griffiths and published by Routledge. This book was released on 2019-01-22 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: An introduction for postgraduate and undergraduate students to the chemical and physical principles of flame and combustion phenomena. This book should be of interest to undergraduate/postgraduate chemists; chemical engineers; undergraduate/postgraduate mechanical engineers and environmental scientists; and industrial combustion technologists.
Download or read book High pressure Soot Formation and Diffusion Flame Extinction Characteristics of Gaseous and Liquid Fuels written by Ahmet Emre Karatas and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Emission Structure and Optical Properties of Overfire Soot from Buoyant Turbulent Diffusion Flames written by Ümit Özgür Köylü and published by . This book was released on 1992 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soot Nanostructure Evolution from Gas Turbine Engine Premixed and Diffusion Flame written by Chung-hsuan Huang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion generated soot impacts human health and climate. Particulate emissions from combustors on jet aircraft are relevant to each area, occurring at ground level and at altitude. One of the advantages of alternative fuels is their potential for reducing emission levels. Comparative field-testing of alternative fuels for their emissions was conducted in the Alternative Aviation Fuel Experiment II (AAFEX II), a NASA-led ground-based field campaign. In this study, particulate emissions from a CFM-56-2C1 engine aboard a DC-9 aircraft were characterized by HRTEM and XPS for nanostructure, carbon speciation and surface chemistry. Fuels studied included JP-8, a 50:50 (JP-8 & HRJ) blend, Hydrotreated Renewable Jet (HRJ), and a Fischer-Tropsch (FT) synthetic fuel. Soot nanostructure and surface chemistry are examined across engine power levels from 4% to 100%. Nanostructure ranged from amorphous (reflecting organic carbon) to graphitic (reflecting elemental carbon) as characterized by lamellae length analysis. With JP-8 fuel, soot particle bonding chemistry, as inferred from the XPS ratio for sp2/sp3 carbon is compared to soot nanostructure evolution. Increasing lamellae length is found to strongly correlate with increasing sp2/sp3 ratio with increasing engine power -- suggesting a change in species identity contributing to the soot growth process. Comparisons between fuels for the same power levels yielded insights into differences in soot processes as dependent upon initial fuel. Soots from the renewable HRJ and FT fuels exhibit significant nanostructure at each power level, rather than the progression as observed for JP-8. This difference is associated with differences in the soot formation environments as dependent upon fuel. To further examine the correlation between chemical environment and soot structure as manifested on different physical length scales, primary particle size versus lamellae length was compared. For JP-8 and its blend with HRJ, there is correlation with engine power, i.e. each spatial metric increases with increasing power, suggesting common underlying cause(s) for both observations. For the HRJ and FT fuels, there is no discernable trend. These results are interpreted in terms of the aromatic content of the JP-8 and blended fuels and their different pyrolysis kinetics compared to paraffinic components of the fuels. Observations of fullerenic nanostructure, particularly evident in soots from the pure paraffinic fuels were interpreted as reflecting partial premixing in order to produce the C5 membered rings for lamellae curvature. This led to the hypothesis defining this study: Partially premixed combustion produces soot with fullerenic nanostructure. Curvature is that one special feature of nanostructure that can be related back to particular gas phase specie(s), namely cyclopentadiene and PAHs containing 5-membered rings.This hypothesis was tested in the following two laboratory flame studies. Partial premixing within simple gas jet diffusion flames has a very long history -- stemming back to the Bunsen flame. Yet HRTEM data of soot from such flames appears absent. In the first study cyclopentane was used as fuel to test lamellae curvature dependence upon C5 species. Modest curvature was observed -- given competing fuel pyrolysis and ring dehydrogenation to yield cyclopentadiene, referred to as C5. Using benzene as the primary fuel with partial premixing tested the chemical path for C5 production -- proceeding through partial benzene oxidation yielding the phenoxy radical followed by CO loss to produce C5. A strong variation of lamellae curvature with oxygen content in the primary fuel stream was observed -- reflecting the increasing C5 production rate. Generality of the nanostructure dependence upon partial premixing and associated change in gas phase chemistry (compared to pure thermal pyrolysis) was demonstrated using an ordinary laboratory Bunsen burner with ethylene as fuel. In absence of partial premixing, soot production is well described by the HACA mechanism, C6 PAHs with observed flat lamellae, without curvature, dissimilar to observations here accompanying partial premixing.In the third study, the main goal was to test two main parameters -- adiabatic flame temperature (2000K) and fuel/air equivalence ratio ([phi] = 2.0) -- for their relative impact on soot nanostructure formation. The soots were collected from a burner-stabilized flat flame burning the petroleum-based JP-8, synthetic FT, and surrogate -- iso-Octane/n-Dodecane, m-Xylene/n-Dodecane, and n-Dodecane -- fuels on a McKenna burner. Images from high-resolution transmission microscopy (HRTEM) show that for the same equivalence ratio of [phi] = 2.0 with temperature maintained constant, soot from the FT fuel has significant curvature compared to soot from the JP-8 fuel, as also found in FT-derived soot from the jet engine. This comparative observation indicates two major findings. First is that the soot nanostructure depends upon initial fuel composition -- and by extension molecular structure. Similar findings from diesel engine studies have also been documented by Yehliu (2010) 1. Second is that fuel pyrolysis pathways and products also depend upon the fuel components. Adjustment of flame adiabatic temperature suggests a temperature threshold for realization of such differences. Soot nanostructure comparisons with a surrogate fuel mixture of n-dodecane/m-xylene (75:25 wt.%) further illustrate pyrolysis processes and intermediates as dependent upon fuel molecular structure and components present. To further compare the experimental results, CHEMKIN with the SERDP mechanism using the burner-stabilized flame model was carried out and processed for the three surrogate fuels, iso-Octane, n-Dodecane, and m-Xylene at various reaction temperatures and fuel/air equivalence ratios. Both the C5H5/C6H6 ratio and C3H3 profiles were distinctly different between the pure n-dodecane and m-xylene/n-dodecane mixture. That the C3H3 profile is also the main difference between the iso-octane and surrogate fuel mix suggests that C3H3 participation in 5-membered ring formation is also key to introduction of 2-D curvature in lamella -- especially given that the highest curvature is observed for FT fuel soot. Moreover, by these results the higher C5H5 observed for the surrogate mixture is an inferred consequence of the different C3H3 profile. Presently these calculated values are only used to interpret the observed curvature differences, as threshold values or the concentration dependency of curvature upon particular species are currently unknown.The goal of this study was to build a bridge between molecular gas phase species and the soot nanostructure. Initial observations of nanostructure curvature in jet engine soot prompted interest. Current chemical kinetic models can address fuel breakdown, thermal and oxidatively assisted, PAH formation and growth all via detailed kinetics, followed by soot inception via their physical and chemical coalescence. Thereafter soot models are particle based and use measured growth rates and aerosol dynamics to account for increasing soot mass and aggregate formation. No modeling studies have yet addressed the link between gas phase species with any aspect of soot nanostructure. As shown here soot nanostructure can reflect its origin, specifically the species forming the soot lamellae. The novelty of two-dimensional curvature is that it can be related uniquely to C5 species, via known chemical pathways -- involving oxygen directly or indirectly. The oxygen concentration in the primary fuel stream defines the level of partial premixing. Therein lies the origin of the hypothesis that partial premixing leads to (recognizable) curvature in soot lamellae. Definition of the operative range of [phi] and temperature will constitute future work for C5 production and its manifestation as curvature in nanostructure.
Download or read book Soot Formation in Combustion written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:
Download or read book Detailed Studies of Soot Formation in Laminar Diffusion Flames for Application to Modeling Studies written by and published by . This book was released on 1996 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of soot formation in laminar diffusion flames showed that soot particle surface growth under laminar diffusion flame conditions ceases because of the depletion of hydrocarbon species and not soot particle reactivity loss due to thermal aging of the particles. This result was obtained through direct species concentration measurements under well-controlled conditions, while the particle reactivity effects were calculated based on premixed flame results along with particle temperature/time information available from earlier laminar diffusion flame studies. Comparisons with a soot formation model which incorporated detailed chemistry effects showed good agreement in terms of predicted and measured species concentration and soot particle field evolution. In addition, a novel technique for measuring soot volume fraction was developed based on laser-induced incandescence and was successfully applied to similar laminar diffusion flame studies. This technique was extended to droplet and turbulent diffusion flame conditions where a two-dimensional imaging approach was employed to measure soot volume fraction. Finally, the complete data set from these studies was assembled in a form suitable for dissemination on computer diskettes throughout the research community for comparison with modeling efforts.
Download or read book Modeling of Soot Formation in Turbulent Diffusion Flames Impinging on a Cold Surface written by Roytor Charoensin-O-larn and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Soot in a Turbulent Diffusion Flame written by Kamran Shamsavari and published by . This book was released on 1976 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
